Personal sampler for NO_x

Abstract

A personal sampler system for NOx (NO + NO2) and NO2 has been developed for monitoring workplace air. The NO2 sampler previously reported from this laboratory uses triethanolamine to trap NO2 which diffuses through a tube of appropriate dimensions. The NOx sampler contains the same elements as the NO2 device, but it is also fitted with a chromic acid impregnated disc; this disc converts NO to NO2 which is then trapped by the triethanolamine along with preformed NO2. The trapped NO2 in all cases is determined as nitrite colorimetrically and NO is measured by difference between the NOx and NO2 values. The NOx sampler gives accurate and reproducible results if the chromic acid disc is in place for 24 hours or less; it is necessary, therefore, to insert and remove the disc within reasonably short times before and after sampling. We believe, however, that this operation will not be a serious problem for the user.

El uso de perceptrones multicapa para la modelización estadística de series de tiempo no lineales de SO2, en Salta Capital, Argentina

“…Se utilizaron tubos tipo Palmes de acrílico ( [3,4]), construidos en nuestro laboratorio con tubos de acrílico de 7 cm de longitud y 12 mm de diámetro interno. En un extremo, sostenidos con una tapa de polietileno, se ubicaron dos discos de malla de acero inoxidable (0,2 x 0,2 mm) humedecidas con una mezcla trietanolamina (90% p/v), mientras que el otro extremo se selló con otra tapa similar.…”

Health hazard evaluation report: HETA-88-104-2207, ASARCO - Troy Unit Mine, Troy, Montana.

“…These samplers measured the workers' exposures to respirable silica, NO, NO 2 , and noise. The sampling and analytical methodologies (2,3,4,5,6) are presented in Table 1.…”

Health hazard evaluation report: HETA-88-108-2146, ASARCO New Market/Young Mines, Mascot, Tennessee.

“…Copies of this report have been sent to: (Cyclone/Impactor) NIOSH Method 7500 (5) Oxides of Nitrogen Passive Chromic acid disc (N0 x , NO, NO 2 ) Sampler Triethanolamine Visible Absorption (Passive Dosimeter) Spectrophotometry (3,4) Nitrogen Dioxide 100 cc/stroke Short-Term Detector Tube Direct Reading (6) Carbon Monoxide 0.02 Long-Term Detector Tube Direct Reading (6) Carbon Monoxide 100 cc/stroke Short-Term Detector Tube Direct Reading (6) Respirable Free 1.7 PVC Filter/Cyclone NIOSH methods 7500/0500, Silica X-Ray Diffraction (5) Notes: LPM-Liters Per Minute NO x Oxides of Nitrogen including, Nitric Oxide (NO), and Nitrogen Dioxide (NO 2 ). (8) MSHA STANDARD (2) Coal Tar A -All samples were collected on operated equipment or in areas where equipment was operating.…”

“…Nitric oxide and nitrogen dioxide were collected using the Palmes (3,4) passive dosimeter. The passive dosimeters are rigid, cylindrical, plastic tubes with a mesh screen at one end of the tube that is coated with triethanolamine.…”